1. Field of the Invention
The present invention relates to semiconductor devices. More particularly, the present invention relates to semiconductor devices that generate electrical signals in response to incident radiation. The invention is particularly applicable to devices that determine the angle-of-arrival of an incident laser beam with high angular resolution (typically referred to as a “HARLID”).
2. State of the Art
A Laser Warning Receiver (LWR) is an important asset of modern military forces for protecting vehicles, weapon platforms, and/or personnel against laser guided weapons. The LWR employs a device that determines the angle-of-arrival of an incident laser beam with high angular resolution (typically referred to as a “HARLID”) in order to accurately locate the laser guided weapon and optimize countermeasures against such laser guided weapon.
The angle-of-arrival of the incident laser beam is typically measured by a device that employs a mask that blocks incident radiation (within the spectral range of interest). The mask includes one or several apertures positioned above at least one array of radiation detectors. The apertures (sometimes referred to as windows or slots) allow the incident radiation to pass through the mask for detection by the radiation detectors. The angle-of-arrival of the incident laser beam is determined from the position where the aperture(s) is(are) imaged onto the radiation detectors. For increased spectral sensitivity, two separate arrays of radiation detectors are commonly used (i.e., an array of silicon photodiodes and an array of GaAs photodiodes), which significantly increases the cost of the device. Moreover, the outputs of the radiation detectors of the device are processed by signal processing circuitry in order to determine the angle-of-arrival of the incident laser beam. Such signal processing circuitry is complex and expensive to develop and manufacture, which also adds to the costs of the device.